Annunciator control system with acknowledgement

ABSTRACT

An annunciator system comprising: an electrical power source; a plurality of monitoring circuits connected to the power source for monitoring a plurality of conditions; and a lock-out circuit commonly connected to the power source and each of the monitoring circuits. Each of the monitoring circuits may comprise a relay responsive on the presence of an abnormal condition associated with its respective circuit to actuate an indicator device in such respective circuit. The lock-out circuit may comprise a relay responsive on the response of one of the monitoring circuit relays, to an abnormal condition, to connect all monitor relays, except the first responsive one, to the power source, locking them in a non-responsive condition. An acknowledgment switch, which may be provided in the lock-out circuit, is positionable to prevent response of the lock-out circuit relay so as to allow independent response of all of the montoring circuit relays to abnormal conditions.

United States Patent 1191 Beeloo Feb. 19, 1974 [54] ANNUNCIATOR CONTROLSYSTEM WITH ACKNOWLEDGEMENT Primary Examiner-Harold l. Pitts [7 51Inventor: Leendert A. Beeloo, Los Angeles, Attorney Agent firm-RalphBrowning Calif. [57] ABSTRACT [73] Assigneez Rotoflow Corporaton, LosAngeles, A I l 1 Cam. n annunclator system compr1s1ng an e ectnca powersource; .a plurallty of mon1tor1ng circuits con- [22] Filed: Apr. 12,1971 nected to the power source for monitoring a plurality ofconditions; and a lock-out circuit commonly con- [211 App! 133251 nectedto the power source and each of the monitoring circuits. Each of themonitoring circuits may com- [52] US. Cl. 340/2131 R, 340/415 R prise arelay responsive on the presence of an abnor- [51] Int. Cl. G081) 23/00mal condition associated with its respective circuit to [58] Field ofSearch 340/415 A, 213 R actuate an indicator device in such respectivecircuit. The lock-out circuit may comprise a relay responsive {56]References Cited on the response of one of the monitoring circuit re- NlE STATES PATENTS lays, to an abnormal condition, to connect all monitor3,537,029 10/1970 Lee 340 2131 relays m the first. responswe n the3,603,948 9/1971 Medlinski... 340/213 R source, lockmg them in anon-responswe cond1t1on. 3,631,432 12 1971 Stallebrass 340 2132 Allacknowledgment Switch, which y be Provided in 3,474,299 10/1969 Caputo340/415 X the lock-out circuit, is positionable to prevent re- 3,474,44310/ 1969 Lightner 340/415 sponse of the lock-out circuit relay so as toallow inde- 3,524,185 8/1970 Ehni 4 5 pendent response of all of thementoring circuit relays Porter.... X to abnormal conditions 3,611,36410/1971 Jones 340/415 3,624,626 11 1971 MacCreadie 340 415 x 21 (31mm, 1Drama Figure i 7 1 Y I L2 ,2 2 2 Q E g lTDRZ-a ,3 l A VA ..V' a .n. NJ 1.If 70/22 j 6666 4r 1 1 1 2 R2-d g- 6m 1+.1 l R2 RZ-a RZ-b i 1 R2-cR-L-f l [I i 1 L! 5) mm -11 1 P52 ----11- [j +JLVW-11- H"'** RI-e 1 RL 01 ,./m7y\* 4 A 6 mm 7 RI-d nm n fl-M 1- g RI 5 Rl-a 5 M ,0

L 1 I .VJ'\ 4 J+V Q Rl-b 1 R-L-c PB! -11 -H'5 l-q'fv'if W4, I Rr-c R-L-eR-Ld R-L l l 5 1 ANNUNCIATOR CONTROL SYSTEM WITH ACKNOWLEDGEMENTBACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to protective instrumentation systems for machinery.More specifically it relates to an integrated combination of aprotective system with an annunciator for indicating first out ofabnormal conditions.

2. Description of the Prior Art Machinery and processes often haveprotective instrumentation such as pressure switches, temperatureswitches, tachometer, level switches, etc., to provide shutdown signalsfor the protection of the machinery or process if an abnormal conditionoccurs. If one of the sensors is activated it may initiate shutdown ofthe machinery or process and also give an alarm signal such as a horn orblinking light. Such machinery or processes often operate unattended andif an abnormal condition occurs, it is not uncommon for one or moreother abnormal conditions to be created. Since several abnormalconditions may activate a number of signals, it is important to knowwhich signal was activated first, to eliminate the basic problem. Thismay be referred to as first out indication.

Abnormal operating conditions may be sensed in such a manner as toilluminate lights or activate other types of signals. For example, a lowoil pressure alarm could activate the standby lube oil pump (which locksin to prevent cycling), and the light showing that the lube oil pump isrunning would then serve as an indication that such an abnormalcondition occurred. Since the lube oil pump locks in, one could laterobserve that this event has taken place because it was still locked in.(Locked in means that when the event took place it also initiated anirreversible cycle such as completing a circuit through a relay whichhas an extra pair of contacts on the relay itself so connected that therelay will not open again until the circuit is broken as by means of apush button.) Presently used annunciator systems where the first out isshown, require extensive wiring installation with separate wiring andrelays for each of the signals. One example of a conventionalannunciator system is described in U. S. Pat. No. Re.24,03l Marmorstone.The annunciator system keeps track of the signals and indicates whichare activated and which was first. After an acknowledge button is pushedthen the special indication of the first is removed. Since theconventional annunciator system requires separate wiring installation,it is relatively expensive.

More recent developments in annunciator systems may be seen in U. S.Pat. Nos. 3,138,791 Beguin; 3,474,443 -Lightner et al; and 3,500,469Plambeck et al. However, for various reasons, including cost,complexity, fail safe operation, etc., a completely satisfactoryreplacement of the conventional system has not, prior to the presentinvention, been found.

SUMMARY OF THE INVENTION The annunciator of the present inventionutilizes a common lockout relay and eliminates the need for a separatelywired system, resulting in a significant cost reduction. The presentinvention utilizes a series of conventional relays each responding toits respective shutdown signal. Each relay is provided with a pair ofnormally open contacts such that when one closes it initiates theshutdown sequence. A corresponding light on a display panel shows whichsignals have been actuated. A second pair of contacts on each relay isso connected that the relay is locked in when it receives a signal andis activated. Its respective panel light is illuminated and is notturned off until an acknowledge button is pressed to release the relayfrom its locked in condition.

Not only is the present invention capable of providing an indication ofabnormal conditions, it identifies which conditions occurred first andwhichconditions still prevail at the time of acknowledgement. Anindicator light is provided for each condition which might shut thesystem down. Also provided is a common relay system which responds tothe first signal actuated. The relay system responds in two ways,locking in the light circuit so that no other subsequently occurringshutdown signal will actuate its light or other indicator and lockingthe relay itself in. When the acknowledge button is pressed all of theemergencylight circuits are re-.

leased and free to respond, no longer being locked out.

- Therefore any emergency abnormal conditions which are still present,including the one respondedto first, are indicated. Thus, the operatormay correct those abnormal conditions which still prevail.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF A PREFERRED EMBODIMENTReferring now to the drawing, a description of the invention will begiven for a system having two emergency shutdown signals. The individualcircuitryfor one is enclosed in the dashed area I and the circuitry forthe other is enclosed in the dashed area II. Common circuitry liesoutside of these dashed areas. As will be seen hereafter the firstabnormal condition to occur will illuminate a signal light, and preventany subsequently occurring condition from illuminating its light orlocking itself in.

For descriptive purposes, it will be assumed that the abnormal conditionindicated by the circuitry in area I occurs first. Relay R1 is actuatedunder normal operation by virtue of the actuating circuit beinginitiated through station contacts 1, normally closed contact Rl-b andnormally closed contact R-L-c hence to the power lines P, P Initialactuation of relay R1 breaks this actuating circuit by opening Rl-b; butit simultaneously closes contact Rl-a which maintains the actuation ofrelay R1 by establishing a connection directly to the power line P Thus,relay R1 is locked in its actuated condition. The relay R1 should be soadjusted that contact Rl-b would not be opened any significant length oftime before contact Rl-a was closed.

Indicator light L1 is on until station contact 1 is closed. Suchclosure, as described above, causes relay R1 to become actuated (andlocked in). Thus contact Rl-d is opened and light L1 is turned off(until an emergency breaks contact 1). Additional station contacts andtheir respective circuitry could be used and would act independently.Although station contact I is shown as a normally open contact, it couldbe a normally closed one. However with the normally open contact it is afail safe energized system.

As stated earlier, one faeature of the inventionrelates to a method forpreventing all but the first occurring abnormal condition fromilluminating respective signal lights. To accomplish this objective acommon relay R-L and time delay relay TDRl is provided. Any emer gencywhich opens station contact 1 breaks the circuit through relay R1 and,among other things, closes contact Rl-d. This illuminates light Ll, butmore importantly, it actuates common relay R-L( by way of normallyclosed contacts TDRl-a and R-Ld). This actuation of relay R-L closescontact R-L-a and thereby locks itself in (until the circuit is openedby depression of acknowledge button PBl). It opens contact R-L-c whichsupplies power to relay Rl preventing it from being reactivated byclosure of station contact 1 (or a disturbance of any other stationcontact).

The normally closed contact feature will open invention relates a secondor two, not disturbing relay R-L because the latter is locked in throughcontact R-L-a, and anyway, the initial circuit to relay R-L wasimmediately broken by the opening of normally closed contact R-L-d. Thisopening of contact TDRl-a permits use of acknowledge button P131 tounlock relay R-L so as to silence the horn H and remove the indicationof first out and to then see what other abnormal conditions are still ineffect.

Now referring to the set of circuitry for another abnormal condition,generally shown enclosed in dashed area 11, it can be seen that theopening of station contact 2 will not deenergize relay R2 because of theparallel circuit through contacts R2-c and R-lL-f Normally open contactsR2-c and R-L-f are now closed because emergency opening of stationcontact 1 activated relay R-L as explained heretofore. Thus, theintroduction of relay R-L made it possible to lock out all emergencylights except the first one.

In order to reset relay R-L by depressing acknowledge button PBl, thepower to relay R-L through lines 3, 4 and 5 must be interrupted. This isaccomplished by providing time delay relay TDRI in parallel withindicator light L1 as shown, having a normally closed contact TDRl-a inline 3. The time delay period should be longer than the short closureperiod for relay R1 but shorter than any-expected operator response todepress button PB]. It should also be longer than the probable durationof a test of lights L1, L2 and horn H through depression of test buttonP82. Then relay R-L can be reset (deactivated) by depressing PBl.

It would be possible to provide a contact on relay R-L which would notopen until R-L-a closes, serving in place of contact TDRl-a. However,then PBl acknowledge would not function. Furthermore, there are usuallya number of abnormal condition station contacts with their individualsets of circuitry in each system. Each set has need for a contactsimilar to TDRl-a. Relay R-L already has one contact in each set andneeds three more besides. An additional contact for each set would betoo many contacts for one relay and at least two would be needed. Theywould be more expensive and occupy more space in expensiveexplosion-proof boxes. Thus, the simple little time delay relay in eachcircuitry set has obvious advantages and accomplishes things the big ordouble R-L relay system could not do.

When light L1 is illuminated, relay R-L is simultaneously closed. RelayTDRl is energized but it delays opening the power circuit to relay R-Lthrough contact TDRl-a for a second or so to allow relay R-L to haveavailable power to close and establish an alternate power circuitthrough contact R-L-a. Normally closed contact R-L-d opens immediatelyto interrupt this initial power signal to relay R-L. Without it openingthere would be power available from contact R-L-a to line 4, thenthrough other time delay relay contacts, TDRZ-a in this case, to thecorresponding time delay relays and lights, causing them to blink. Whencontacts TDRl-a opens it removes the power supply from line 4.

Also shown is a test button PB2, to demonstrate that additional featuresmay be added to the circuitry of the invention without complication. Thedepression of test button PBZ permits testing of all lights L1, L2, thelockin circuitry and horn H.

It is believed obvious to those skilled in the art that additionalcircuits for abnormal conditions could be added as illustrated by theabove described second set of circuitry ll. The additional circuitswould be added on in the same manner that the second one ll is added on.Similarly, it is obvious that an alarm system (instead of or in additionto a shutdown system) might be controlled by the invention. Othervariations should be obvious to those skilled in the art and it isintended that the scope of the invention be limited only by the claimswhich follow.

I claim:

1. An annuciator system, operable on AC. or D. C. current, forindicating the presence of abnormal conditions in a plurality ofmonitored conditions and, when more than one abnormal condition occurs,indicating which occurred first, comprising: a source of electricalpower; a plurality of monitoring circuits for said plurality ofmonitored conditions connected to said electrical power source; controlmeans in each monitoring circuit responsive on the presence of anabnormal condition associated with its respective circuit to actuateindicator means in said respective circuit; a lock-out circuit commonlyconnected to said plurality of monitoring circuits and said power sourceand including lock-out control means responsive on the actuation of oneof said indicator means to prevent response of the control means in eachof the other monitoring circuits to subsequent abnormal conditions;acknowledgement means in said lock-out circuit, positionable to preventsaid response of said lock-out control means so as to allow independentresponse of all of said monitoring control means to abnormal conditions.

2. An annuciator system as set forth in claim 1 in which said indicatormeans in each of said monitoring circuits comprises a single indicatordevice.

3. An annunciator as set .forth in claim 1, characterized in that saidlock-out control means comprises a relay in series with its own normallyclosed first contact and in series with a parallel group of normallyclosed first contacts in each of said monitoring circuits to complete afirst circuit from said power source to energize said lockout relay onresponse of any one of said monitoring circuit control means to anabnormal condition, said lock-out relay having a normally open secondcontact in parallel with its said first contact closeable on theenergization of said relay to connect and lock said relay in a secondcircuit with said power source, said first relay contact being openedupon said relay energization to prevent power from flowing back to saidmonitoring circuits through said first circuit.

4. An annunicator as set forth in claim 3, characterized by a time delayrelay in each of said monitoring circuits having a normally closedcontact in series with said monitoring circuit first contacts, said timedelay relays being self-actuating after a selected period of time, fromresponse of its respective monitor control means, to open said timedelay relay contact, interrupting power to said lock-out relay throughsaid first circuit.

5. An annunciator as set forth in claim 3, characterized in that saidlock-out relay comprises a set of normally open third contacts, one foreach of said monitoring circuits, connected to the control means of eachmonitoring circuit and closeable upon the energization of said lock-outrelay to lock all of said monitor control means, except the first torespond to an abnormal condition, in a non-responsive condition.

6. An annunciator as set forth in claim 3, characterized in that saidacknowledgement means comprises a switch in series with said lock-outrelay and operable to interrupt power to said lock-out relay, unlocksaid lock-out relay from said second circuit.

7. An annunciator as set forth in claim 3, characterized in that each ofsaid monitor control means comprises a relay in series with its ownabnormal condition responsive contact and a power circuit forenergization from said power source and which comprises said monitoringcircuit first contacts, said monitor relays being deenergizable inresponse to said presence of an abnormal condition associated with itsrespective circuit to actuate said indicator means and close itsrespective said monitoring circuit first contact for said energizationof said lock-out relay.

8. An annunciator as set forth in claim 7, characterized in that each ofsaid monitor relays comprises a normally open third contact in serieswith its respective indicator means and connected to a common line which7 is connected to said power source through a test switch.

9. An annunciator system for indicating the presence of abnormalconditions in a plurality of monitored conditions and, when more thanone abnormal conditions occurs, indicating which occurred first,comprising: an electrical power source, a plurality of monitoringcircuits connected to said power source for said plurality of monitoredconditions, each comprising a relay responsive on the presence of anabnormal condition associated with its respective circuit to actuate anindicator device in said respective circuit; and a lock-out circuitcommonly connected to said power source and each of said monitoringcircuits comprising a relay responsive on the response of one of saidmonitor relays, to an abnormal condition, to prevent response of anyother monitor relay to subsequent abnormal conditions; characterized byacknowledgement means in said lock-out circuit actuatable to preventresponse of said lock-out relay to any of said monitor relays so as toallow simultaneous independent response of each of said monitor relaysand its associated indicator device to an abnormal condition.

10. An annunciator system as set forth in claim 9, characterized in thatsaid lock-out relay-comprises a normally closed first contact in serieswith a parallel group of normally closed monitor first contacts, one oneach of said monitor relays, to complete a first circuit from said powersource, for actuating said lock-out relay on the said response of one ofsaid monitor relays to an abnormal condition, said lock-out relay havinga normally open second contact in parallel with said first contactcloseable on actuation of said lock-out relay to connect and lock saidlock-out relay in a second circuit with said power source while saidfirst contact is simultaneously opened to break said first circuit.

11. An annunciator system as set forth in claim 10, characterized inthat said lock-out relay comprises a set of normally open thirdcontacts, one each in series with each of said monitor relays andconnecting its respective monitor relay to said power source onactuation of said lock-out relay to lock all of said monitor relays,except said first responsive one, in a non-responsive condition. 1

12. An annunciator system as set forth in claim 11, characterized inthat each of said monitoring circuits comprises a time delay relayhaving a normally closed contact in series with its respective monitorfirst contact, said time delay relays being self-actuatable, after aselected interval of time on response of its respective monitor relay,to interrupt power from said monitor first contact to said lock-outfirst contact through said first circuit.

13. An annunciator system as set forth in claim 12, characterized inthat said acknowledgement means comprises switch means in series withsaid lock-out relay positionable to interrupt power to said lock-outrelay causing said lock-out third contacts to be opened rendering saidother monitor relays and their respective indicator devices responsiveto abnormal conditions.

14. An annunciator system as set forth in claim 13, characterized inthat each of said monitor relays comprises a normally open contact inseries with its respective indicator device in a line leading to acommon line connected through test switch means to said power source.

15. An annunciator system as set forth in claim 9, characterized in thateach of said monitor relays comprises an abnormal condition responsivestation contact in series with a normally closed first contact connectedto said power source for initial actuation of said monitor relays, eachof said monitor relays comprising a normally open second contact inparallel with said first contact and connected to said power source,actuation of said monitor relay simultaneously opening said firstcontact and closing said second contact to maintain power to saidmonitor relay until interrupted by response of said station contact toan abnormal condition.

16. An annunciator system as set forth in claim 15, characterized inthat said monitor relay comprises a normally closed third contact inparallel with said station contact and said first and second contactsand connected to said power source through one of a set of normally openlock-out contacts on said lock-out relay, said lock-out contacts beingclosed on said lock-out relay response to connect all except said onemonitor relay to said power source through said third contacts,by-passing said station contacts and locking said other monitor relaysin a non-responsive condition.

17. An annunciator system as set forth in claim 15, characterized inthat said indicator device is connected to said power source through anormally closed third contact on said monitor relay.

18. An annunciator system as set forth in claim 17, characterized inthat said monitor relay comprises a normally open fourth contact inparallel with said third contact and through which said indicatingdevice may be connected to said power source through a switch device.

19. An annunciator system as set forth in claim 9 in which saidindicator device in each of said respective circuits comprises a singlelamp.

20. An annunciator system for indicating the presence of abnormalconditions in a plurality of monitored conditions and, when more thanone abnormal condition occurs, indicating which occurred first,comprising: a two terminal power source; a plurality of monitoringcircuits connected to said power source, each comprising a relay havingan abnormal condition responsive station contact in series with anormally closed first contact connected to said power source for initialactuation of its respective relay and a normally closed second contactin series with an indicating device, said second contact being closed onresponse of said station contact to an abnormal condition to actuatesaid indicating device; and a lock-out circuit commonly connected tosaid power source and each of said monitoring circuits and comprising arelay having a normally closed first contact in series with a parallelgroup of contacts, comprising said monitor relay second contacts, tocomplete a first circuit from said power source for actuating saidlock-out relay on the said response of one of said station contacts toan abnormal condition, said lock-out relay comprising a set of normallyopen second contacts, one each in parallel with each of said monitorrelay station and first contacts, closeable on actuation of saidlock-out relay, by response of one of said monitor relays to an abnormalcondition, to connect all of said monitor relays, except said firstresponsive one, to said power source, locking them in a non-responsivecondition; characterized in that each of said monitoring circuitscomprises a time delay relay having a normally closed contact in serieswith its respective monitor relay second contact, the time delay relayassociated with said one monitor relay being self-actuatable after aselected interval of time from actuation of said lock-out relay tointerrupt power to said lock-out relay through said first circuit.

21. An annunciator system as set forth in claim 20, characterized byacknowledgement switch means in series with said lock-out relay,positionable to interrupt all power to said lock-out relay, opening saidlock-out relay second contacts and rendering said other monitor relaysresponsive to abnormal conditions.

UNITED STATES PATENT OFFICE (IEWII FICATE ()F CORRECTION Patent No.3,793,633 Dated February 19, 197

lnv n fl Leendert A. Beeloo It is certified that error appears in theabove-identified patent and that said Letters Patentare hereby correctedas shown below:

In column 1, line 59, delete "been" and insert therefor --been--.

In column 3, line I, delete "faeature" and insert-therefor --feature--;delete "inventionrelates" and insert therefor invention relates-'--.

In column 3, line 17, delete "feature" and insert therefor --TDRl-a--;delete "inven-".

In column 3, line 18, delete "tion relates" and insert therefor -in-.

In column 5, line 21, Claim 6, delete "unlock" and insert therefor"unlocking-e.

In column 5, line #1, Claim 9, delete "conditions" and insert therefor-cond-ition-.

Signed and sealed this 17th day of September 1974.

(SEAL) Attest:

MCCOY M. GIBSON JR. 3 C, MARSHALL DANN Attesting Officer Commissioner ofPatents FORM Po-wso {10-69) USCOMMDC 603mm U 5 GOVERNMENT PRINTINGOFFlCE 1969 ?-.EE1-334

1. An annuciator system, operable on A.C. or D. C. current, forindicating the presence of abnormal conditions in a plurality ofmonitored conditions and, when more than one abnormal condition occurs,indicating which occurred first, comprising: a source of electricalpower; a plurality of monitoring circuits for said plurality ofmonitored conditions connected to said electrical power source; controlmeans in each monitoring circuit responsive on the presence of anabnormal condition associated with its respective circuit to actuateindicator means in said respective circuit; a lock-out circuit commonlyconnected to said plurality of monitoring circuits and said power sourceand including lockout control means responsive on the actuation of oneof said indicator means to prevent response of the control means in eachof the other monitoring circuits to subsequent abnormal conditions;acknowledgement means in said lock-out circuit, positionable to preventsaid response of said lock-out control means so as to allow independentresponse of all of said monitoring control means to abnormal conditions.2. An annuciator system as set forth in claim 1 in which said indicatormeans in each of said monitoring circuits comprises a single indicatordevice.
 3. An annunciator as set forth in claim 1, characterized in thatsaid lock-out control means comprises a relay in series with its ownnormally closed first contact and in series with a parallel group ofnormally closed first contacts in each of said monitoring circuits tocomplete a first circuit from said power source to energize said lockoutrelay on response of any one of said monitoring circuit control means toan abnormal condition, said lock-out relay having a normally open secondcontact in parallel with its said first contact closeable on theenergization of said relay to connect and lock said relay in a secondcircuit with said power source, said first relay contact being openedupon said relay energization to prevent power from flowing back to saidmonitoring circuits through said first circuit.
 4. An annunicator as setforth in claim 3, characterized by a time delay relay in each of saidmonitoring circuits having a normally closed contact in series with saidmonitoring circuit first contacts, said time delay relays beingself-actuating after a selected period of time, from response of itsrespective monitor control means, to open sAid time delay relay contact,interrupting power to said lock-out relay through said first circuit. 5.An annunciator as set forth in claim 3, characterized in that saidlock-out relay comprises a set of normally open third contacts, one foreach of said monitoring circuits, connected to the control means of eachmonitoring circuit and closeable upon the energization of said lock-outrelay to lock all of said monitor control means, except the first torespond to an abnormal condition, in a non-responsive condition.
 6. Anannunciator as set forth in claim 3, characterized in that saidacknowledgement means comprises a switch in series with said lock-outrelay and operable to interrupt power to said lock-out relay, unlocksaid lock-out relay from said second circuit.
 7. An annunciator as setforth in claim 3, characterized in that each of said monitor controlmeans comprises a relay in series with its own abnormal conditionresponsive contact and a power circuit for energization from said powersource and which comprises said monitoring circuit first contacts, saidmonitor relays being deenergizable in response to said presence of anabnormal condition associated with its respective circuit to actuatesaid indicator means and close its respective said monitoring circuitfirst contact for said energization of said lock-out relay.
 8. Anannunciator as set forth in claim 7, characterized in that each of saidmonitor relays comprises a normally open third contact in series withits respective indicator means and connected to a common line which isconnected to said power source through a test switch.
 9. An annunciatorsystem for indicating the presence of abnormal conditions in a pluralityof monitored conditions and, when more than one abnormal conditionsoccurs, indicating which occurred first, comprising: an electrical powersource, a plurality of monitoring circuits connected to said powersource for said plurality of monitored conditions, each comprising arelay responsive on the presence of an abnormal condition associatedwith its respective circuit to actuate an indicator device in saidrespective circuit; and a lock-out circuit commonly connected to saidpower source and each of said monitoring circuits comprising a relayresponsive on the response of one of said monitor relays, to an abnormalcondition, to prevent response of any other monitor relay to subsequentabnormal conditions; characterized by acknowledgement means in saidlock-out circuit actuatable to prevent response of said lock-out relayto any of said monitor relays so as to allow simultaneous independentresponse of each of said monitor relays and its associated indicatordevice to an abnormal condition.
 10. An annunciator system as set forthin claim 9, characterized in that said lock-out relay comprises anormally closed first contact in series with a parallel group ofnormally closed monitor first contacts, one on each of said monitorrelays, to complete a first circuit from said power source, foractuating said lock-out relay on the said response of one of saidmonitor relays to an abnormal condition, said lock-out relay having anormally open second contact in parallel with said first contactcloseable on actuation of said lock-out relay to connect and lock saidlock-out relay in a second circuit with said power source while saidfirst contact is simultaneously opened to break said first circuit. 11.An annunciator system as set forth in claim 10, characterized in thatsaid lock-out relay comprises a set of normally open third contacts, oneeach in series with each of said monitor relays and connecting itsrespective monitor relay to said power source on actuation of saidlock-out relay to lock all of said monitor relays, except said firstresponsive one, in a non-responsive condition.
 12. An annunciator systemas set forth in claim 11, characterized in that each of said monitoringcircuits comprises a time delay relay having a normally closed contactin series with its respectiVe monitor first contact, said time delayrelays being self-actuatable, after a selected interval of time onresponse of its respective monitor relay, to interrupt power from saidmonitor first contact to said lock-out first contact through said firstcircuit.
 13. An annunciator system as set forth in claim 12,characterized in that said acknowledgement means comprises switch meansin series with said lock-out relay positionable to interrupt power tosaid lock-out relay causing said lock-out third contacts to be openedrendering said other monitor relays and their respective indicatordevices responsive to abnormal conditions.
 14. An annunciator system asset forth in claim 13, characterized in that each of said monitor relayscomprises a normally open contact in series with its respectiveindicator device in a line leading to a common line connected throughtest switch means to said power source.
 15. An annunciator system as setforth in claim 9, characterized in that each of said monitor relayscomprises an abnormal condition responsive station contact in serieswith a normally closed first contact connected to said power source forinitial actuation of said monitor relays, each of said monitor relayscomprising a normally open second contact in parallel with said firstcontact and connected to said power source, actuation of said monitorrelay simultaneously opening said first contact and closing said secondcontact to maintain power to said monitor relay until interrupted byresponse of said station contact to an abnormal condition.
 16. Anannunciator system as set forth in claim 15, characterized in that saidmonitor relay comprises a normally closed third contact in parallel withsaid station contact and said first and second contacts and connected tosaid power source through one of a set of normally open lock-outcontacts on said lock-out relay, said lock-out contacts being closed onsaid lock-out relay response to connect all except said one monitorrelay to said power source through said third contacts, by-passing saidstation contacts and locking said other monitor relays in anon-responsive condition.
 17. An annunciator system as set forth inclaim 15, characterized in that said indicator device is connected tosaid power source through a normally closed third contact on saidmonitor relay.
 18. An annunciator system as set forth in claim 17,characterized in that said monitor relay comprises a normally openfourth contact in parallel with said third contact and through whichsaid indicating device may be connected to said power source through aswitch device.
 19. An annunciator system as set forth in claim 9 inwhich said indicator device in each of said respective circuitscomprises a single lamp.
 20. An annunciator system for indicating thepresence of abnormal conditions in a plurality of monitored conditionsand, when more than one abnormal condition occurs, indicating whichoccurred first, comprising: a two terminal power source; a plurality ofmonitoring circuits connected to said power source, each comprising arelay having an abnormal condition responsive station contact in serieswith a normally closed first contact connected to said power source forinitial actuation of its respective relay and a normally closed secondcontact in series with an indicating device, said second contact beingclosed on response of said station contact to an abnormal condition toactuate said indicating device; and a lock-out circuit commonlyconnected to said power source and each of said monitoring circuits andcomprising a relay having a normally closed first contact in series witha parallel group of contacts, comprising said monitor relay secondcontacts, to complete a first circuit from said power source foractuating said lock-out relay on the said response of one of saidstation contacts to an abnormal condition, said lock-out relaycomprising a set of normally open second contacts, one each in parallelwith each of said monitor relay station And first contacts, closeable onactuation of said lock-out relay, by response of one of said monitorrelays to an abnormal condition, to connect all of said monitor relays,except said first responsive one, to said power source, locking them ina non-responsive condition; characterized in that each of saidmonitoring circuits comprises a time delay relay having a normallyclosed contact in series with its respective monitor relay secondcontact, the time delay relay associated with said one monitor relaybeing self-actuatable after a selected interval of time from actuationof said lock-out relay to interrupt power to said lock-out relay throughsaid first circuit.
 21. An annunciator system as set forth in claim 20,characterized by acknowledgement switch means in series with saidlock-out relay, positionable to interrupt all power to said lock-outrelay, opening said lock-out relay second contacts and rendering saidother monitor relays responsive to abnormal conditions.